Your music
openDJ reads your ~/Music folder. To use another folder, start openDJ with
the OPENDJ_MUSIC environment variable:
OPENDJ_MUSIC=/path/to/music opendj
The Files source on the left of the library lets you browse any folder on your computer and load tracks from it.
The library
Your library keeps playlists, smart lists, ratings, colours and play history.
Search matches titles, artists, BPM and key. The ? next to the search box lists everything search understands.